Merge pull request #588 from btsimonh/refcount

Refcount

examples/matrix-ref-count.js

@@ -0,0 +1,27 @@
+var cv = require('../lib/opencv');
+
+cv.readImage('./files/mona.png', function(err, im) {
+  if (err) throw err;
+  if (im.width() < 1 || im.height() < 1) throw new Error('Image has no size');
+
+
+  // getrefCount will give the refcount.  if > 0, then a reference ptr is present, and the value returned.
+  // if -1, no reference pointer was present (i.e. the mat does not know about any data).
+  var refcount = im.getrefCount();
+  console.log('initial refcount '+refcount);
+  if (refcount !== 1)
+	  throw "refcountmismatch - initial should be 1";
+  
+  im.release();
+  var refcount3 = im.getrefCount();
+  console.log('refcount after release (seems should be -1) '+refcount3);
+  if (refcount3 !== -1)
+	  throw "refcountmismatch - after release should be -1";
+
+  // data is now still there somewhere, but lost to us - this is NOT a good situation.
+
+  // should not fail - but will do absolutely nothing
+  im.release();
+  
+  console.log('did all refcount tests');
+});

src/Matrix.cc

@@ -117,7 +117,10 @@ void Matrix::Init(Local<Object> target) {
   Nan::SetPrototypeMethod(ctor, "mean", Mean);
   Nan::SetPrototypeMethod(ctor, "shift", Shift);
   Nan::SetPrototypeMethod(ctor, "reshape", Reshape);
+// leave this out - can't see a way it could be useful to us, as release() always completely forgets the data
+//  Nan::SetPrototypeMethod(ctor, "addref", Addref);
   Nan::SetPrototypeMethod(ctor, "release", Release);
+  Nan::SetPrototypeMethod(ctor, "getrefCount", GetrefCount);
   Nan::SetPrototypeMethod(ctor, "subtract", Subtract);
   Nan::SetPrototypeMethod(ctor, "compare", Compare);
   Nan::SetPrototypeMethod(ctor, "mul", Mul);
@@ -3027,6 +3030,42 @@ NAN_METHOD(Matrix::Release) {
   return;
 }
 
+// leave this out - can't see a way it could be useful to us, as release() always completely forgets the data
+//NAN_METHOD(Matrix::Addref) {
+//  Nan::HandleScope scope;
+//
+//  Matrix *self = Nan::ObjectWrap::Unwrap<Matrix>(info.This());
+//  self->mat.addref();
+//
+//  return;
+//}
+
+
+NAN_METHOD(Matrix::GetrefCount) {
+  Nan::HandleScope scope;
+  Matrix *self = Nan::ObjectWrap::Unwrap<Matrix>(info.This());
+
+  int refcount = -1;
+  
+#if CV_MAJOR_VERSION >= 3
+    if (self->mat.u){
+        refcount = self->mat.u->refcount;
+    } else {
+        refcount = -1; // indicates no reference ptr
+    }
+#else
+    if (self->mat.refcount){
+        refcount = *(self->mat.refcount);
+    } else {
+        refcount = -1; // indicates no reference ptr
+    }
+#endif    
+
+  info.GetReturnValue().Set(Nan::New<Number>(refcount));
+  return;
+}
+
+
 NAN_METHOD(Matrix::Subtract) {
   SETUP_FUNCTION(Matrix)
 

src/Matrix.h

@@ -134,7 +134,11 @@ public:
   JSFUNC(Shift)
   JSFUNC(Reshape)
 
+          
+// leave this out - can't see a way it could be useful to us, as release() always completely forgets the data
+//JSFUNC(Addref)
   JSFUNC(Release)
+  JSFUNC(GetrefCount)
 
   JSFUNC(Subtract)
   JSFUNC(Compare)